Terminal structure for thin film capacitor

Abstract

A kind of terminal post structure of film capacitor, belong to electrical component technical field.The film capacitor includes shell, and the potting layer is potting in the potting cavity;Positive busbar and negative busbar are fixed in the upper portion of potting layer by potting layer, terminal post structure includes positive terminal post and negative terminal post, it is characterized that: the lower end of positive terminal post and around the surface of four around positive terminal post is formed as positive terminal post potting layer anchoring reinforcement surface, the lower end of negative terminal post and around the surface of four around negative terminal post is formed as negative terminal post potting layer anchoring reinforcement surface, the lower end of positive terminal post and negative terminal post is anchored with the potting layer by the positive terminal post potting layer anchoring reinforcement surface and negative terminal post potting layer anchoring reinforcement surface respectively.Advantages: can make positive terminal post and negative terminal post and potting layer present excellent anchoring effect, guarantee pressure resistance performance and moisture resistance performance, so that the service life of film capacitor can be reliably guaranteed.

Description

Technical Field

[0001] This utility model belongs to the field of electrical component technology, specifically relating to a terminal structure for a thin-film capacitor. Background Technology

[0002] With the rapid development of the new energy industry, converters have become an indispensable component. Taking the crucial support capacitor in a converter as an example, it plays a role in energy storage, absorption, and filtering. Especially for the support capacitors of some high-power converters, the operating environment is relatively harsh, with factors such as vibration, force, and thermal shock, which undoubtedly places more stringent requirements on the capacitor structure. Specifically, in existing technologies, the commonly used bolt-type support capacitor consists of multiple capacitor cores connected in parallel, series, or a combination of parallel and series connections, ultimately electrically connected to other devices via bolts that serve as leads.

[0003] As the power of power electronic devices continues to increase, the leads not only need to have larger diameters to meet the output current requirements, but also need to adapt to the changing environmental conditions of different application scenarios, such as vibration and shock. Furthermore, since the leads are typically made of brass, while the encapsulation material is usually epoxy resin, an interface naturally forms between the two. Because brass, as a metallic material, and epoxy resin, as an encapsulation material, are materials with different properties, their coefficients of thermal expansion (also known as "coefficients of thermal expansion") differ, making it easy for annular cracks to form at their interface. In addition, stress accumulation easily occurs at crack sites. If the bonding strength between the metallic material and the encapsulation material is insufficient, radial cracks will appear on the surface of the encapsulation material, centered on the bolt, thus affecting the capacitor's withstand voltage and moisture resistance.

[0004] Based on the above factors, it is of positive significance to explore how to avoid cracking of packaging materials without changing the packaging process and packaging materials. The technical solution to be introduced below was developed in this context. Utility Model Content

[0005] The objective of this invention is to provide a terminal structure for a thin-film capacitor that helps to prevent radial cracks from appearing in the capacitor potting compound around the terminal, thereby ensuring its voltage resistance and moisture resistance.

[0006] The present invention achieves its objective as follows: a terminal structure for a thin-film capacitor, wherein the thin-film capacitor includes a housing having a potting cavity, within which a potting layer is potted; a positive busbar and a negative busbar, the positive and negative busbars being fixed to the upper part of the potting layer in a state that is both corresponding to each other and maintaining a gap between them; the terminal structure includes a positive terminal and a negative terminal, the lower end of the positive terminal engaging with the positive busbar and being potted and bonded to the upper part of the potting layer along with the positive busbar, and the lower end of the negative terminal engaging with the negative busbar. Furthermore, it is encapsulated and bonded to the upper part of the potting layer along with the negative busbar. The upper ends of the positive terminal and the negative terminal protrude from the upper surface of the potting layer. The feature is that the lower end of the positive terminal and the surrounding surface of the positive terminal form an anchoring reinforcement surface for the potting layer, and the lower end of the negative terminal and the surrounding surface of the negative terminal form an anchoring reinforcement surface for the potting layer. The lower ends of the positive terminal and the negative terminal are anchored to the potting layer by the anchoring reinforcement surfaces of the positive terminal and the negative terminal, respectively.

[0007] In a specific embodiment of this utility model, the anchoring reinforcement surface of the positive terminal block potting layer and the anchoring reinforcement surface of the negative terminal block potting layer are of the following structures: knurled texture, ratchet texture, annular groove texture, thread texture, straight knurled texture, or dragon tooth texture.

[0008] In another specific embodiment of this utility model, a positive terminal insertion hole is provided on the positive busbar at a position corresponding to the positive terminal, and a negative terminal insertion hole is provided on the negative busbar at a position corresponding to the negative terminal. The lower end of the positive terminal is fitted with the positive terminal insertion hole and extends to the bottom of the positive busbar and is wrapped by the potting layer. The lower end of the negative terminal is fitted with the negative terminal insertion hole and extends to the bottom of the negative busbar and is wrapped by the potting layer.

[0009] In another specific embodiment of this utility model, a positive terminal extension flange that fits into the hole of the positive terminal is formed at the center of the lower end of the positive terminal, and a negative terminal extension flange that fits into the hole of the negative terminal is formed at the center of the lower end of the negative terminal.

[0010] In another specific embodiment of this utility model, the potting layer is an epoxy resin layer.

[0011] In another specific embodiment of this utility model, the positive busbar and the negative busbar are E-shaped with their positions staggered and face-to-face.

[0012] In a further specific embodiment of this utility model, the positive busbar and the negative busbar are made of copper.

[0013] In a further specific embodiment of this utility model, a positive terminal electrical connection hole is formed at the upper center of the positive terminal, and a negative terminal electrical connection hole is formed at the upper center of the negative terminal.

[0014] In yet another specific embodiment of this utility model, the positive terminal and the negative terminal are made of a metal material with high conductivity and high mechanical strength.

[0015] In yet another specific embodiment of this utility model, the metal material with high conductivity and high mechanical strength is copper or a copper alloy, and the copper alloy is chromium-zirconium copper.

[0016] The technical effect of the solution provided by this utility model is as follows: Since the positive and negative terminals are respectively formed on the lower periphery of the positive and negative terminals, the positive and negative terminals and the encapsulation layer can exhibit excellent anchoring effect. As a capacitor encapsulation material, the encapsulation layer will not have radial cracks centered on the positive and negative terminals, thus ensuring the voltage resistance and moisture resistance, and reliably guaranteeing the service life of the film capacitor. Attached Figure Description

[0017] Figure 1 This is a structural diagram of an embodiment of the present utility model;

[0018] Figure 2 This is a view of the exterior of the present invention.

[0019] In the figure: 1. Outer shell, 11. Encapsulation cavity, 111. Encapsulation layer; 2. Positive busbar, 21. Positive terminal recess; 3. Negative busbar, 31. Negative terminal recess; 4. Positive terminal, 41. Positive terminal encapsulation layer anchoring reinforcement surface, 42. Positive terminal extension flange, 43. Positive terminal electrical connection hole; 5. Negative terminal, 51. Negative terminal encapsulation layer anchoring reinforcement surface, 52. Negative terminal extension flange, 53. Negative terminal electrical connection hole. Detailed Implementation

[0020] In order to better understand the technical essence and beneficial effects of this utility model, the applicant provides a detailed description below by way of embodiments. However, the description of the embodiments is not intended to limit the solution of this utility model. Any formal but not substantive equivalent transformations made based on the concept of this utility model should be considered within the scope of the technical solution of this utility model.

[0021] Please see Figure 1The diagram shows the outer shell 1 of a thin-film capacitor structure, which has a potting cavity 11 in which a potting layer 111 is potted. It also shows a positive busbar 2 and a negative busbar 3, which are fixed to each other by the potting layer 111 in a state that is both corresponding to each other and maintaining a gap between them. The diagram further shows a positive terminal 4 and a negative terminal 5 of a terminal structure. The lower end of the positive terminal 4 engages with the positive busbar 2 and is potted and bonded to the upper part of the potting layer 111 along with the positive busbar 2. The lower end of the negative terminal 5 engages with the negative busbar 3 and is potted and bonded to the upper part of the potting layer 111 along with the negative busbar 3. The upper ends of both the positive terminal 4 and the negative terminal 5 protrude from the upper surface of the potting layer 111.

[0022] The key technical points of the technical solution provided by this utility model are as follows: the lower end of the aforementioned positive terminal 4 and the surrounding surface of the positive terminal 4 constitute a positive terminal potting layer anchoring reinforcement surface 41, and the lower end of the aforementioned negative terminal 5 and the surrounding surface of the negative terminal 5 constitute a negative terminal potting layer anchoring reinforcement surface 51. The aforementioned positive terminal potting layer anchoring reinforcement surface 41 and the negative terminal potting layer anchoring reinforcement surface 51 respectively anchor the lower ends of the positive terminal 4 and the negative terminal 5 to the aforementioned potting layer 111.

[0023] In this embodiment, the aforementioned positive terminal block potting layer anchoring reinforcement surface 41 and negative terminal block potting layer anchoring reinforcement surface 51 have a knurled texture, but they can also be a ratchet texture, annular groove texture, thread texture, straight knurled texture or dragon tooth texture.

[0024] A positive terminal hole 21 is provided on the aforementioned positive busbar 2 at the position corresponding to the aforementioned positive terminal 4. A negative terminal hole 31 is provided on the aforementioned negative busbar 3 at the position corresponding to the aforementioned negative terminal 5. The lower end of the aforementioned positive terminal 4 is fitted with the positive terminal hole 21 and extends to the bottom of the positive busbar 2 and is wrapped by the aforementioned potting layer 111. The lower end of the aforementioned negative terminal 5 is fitted with the negative terminal hole 31 and extends to the bottom of the negative busbar 3 and is wrapped by the aforementioned potting layer 111.

[0025] At the center of the lower end of the aforementioned positive terminal 4, a positive terminal extension flange 42 is formed to fit into the aforementioned positive terminal insertion hole 21. At the center of the lower end of the aforementioned negative terminal 5, a negative terminal extension flange 52 is formed to fit into the aforementioned negative terminal insertion hole 31. The positive and negative terminal extension flanges 42 and 52 are wrapped by the aforementioned potting layer 111 after extending below the positive and negative terminal insertion holes 21 and 31, respectively.

[0026] In this embodiment, the aforementioned potting layer 111 is an epoxy resin layer.

[0027] Depend on Figure 1 As shown, the positive busbar 2 and the negative busbar 3 are E-shaped with their positions staggered and facing each other.

[0028] In this embodiment, the aforementioned positive busbar 2 and negative busbar 3 are made of copper. A positive terminal electrical connection hole is formed at the upper center of the aforementioned positive terminal 4, and a negative terminal electrical connection hole 53 is formed at the upper center of the aforementioned negative terminal 5.

[0029] In this embodiment, the aforementioned positive terminal 4 and negative terminal 5 are made of a metal material with high conductivity and high mechanical strength. Specifically, the metal material with high conductivity and high mechanical strength is copper, but it can also be a copper alloy, such as chromium-zirconium copper.

[0030] Please see Figure 2 , Figure 2 The diagram shown is a schematic representation of the completed process of this utility model. Figure 2 As shown, the upper ends of the aforementioned positive and negative terminals 4 and 5 protrude from the potting layer 111.

[0031] This invention increases the contact area with the potting layer 111 and enhances the anchoring force by modifying the surface structure around the lower ends of the positive and negative terminals 4 and 5. This effectively disperses stress by transforming a large interface into smaller interfaces in different directions. Compared with existing technologies, the packaging process is compatible and requires no updates to related packaging equipment and processes.

Claims

1. A terminal structure for a thin-film capacitor, the thin-film capacitor comprising a housing (1) having a potting cavity (11) in which a potting layer (111) is potted; a positive busbar (2) and a negative busbar (3), the positive busbar (2) and the negative busbar (3) being fixed to the upper part of the potting layer (111) in a state of both corresponding to each other and maintaining a gap between them; the terminal structure comprising a positive terminal (4) and a negative terminal (5), the lower end of the positive terminal (4) engaging with the positive busbar (2) and being potted and bonded to the upper part of the potting layer (111) along with the positive busbar (2); the lower end of the negative terminal (5) engaging with the negative busbar (3) and being potted and bonded to the upper part of the potting layer (111) along with the negative busbar (3), wherein, The upper ends of the positive terminal (4) and the negative terminal (5) protrude from the upper surface of the potting layer (111). The characteristic is that the lower end of the positive terminal (4) and the surrounding surface of the positive terminal (4) form a positive terminal potting layer anchoring reinforcement surface (41), and the lower end of the negative terminal (5) and the surrounding surface of the negative terminal (5) form a negative terminal potting layer anchoring reinforcement surface (51). The lower ends of the positive terminal (4) and the negative terminal (5) are respectively anchored to the potting layer (111) by the positive terminal potting layer anchoring reinforcement surface (41) and the negative terminal potting layer anchoring reinforcement surface (51).

2. The terminal structure of the thin-film capacitor according to claim 1, characterized in that: The positive terminal block potting layer anchoring reinforcement surface (41) and the negative terminal block potting layer anchoring reinforcement surface (51) are of the following structures: knurled structure, ratchet structure, annular groove structure, threaded structure, straight knurled structure or dragon tooth structure.

3. The terminal structure of the thin-film capacitor according to claim 1, characterized in that: A positive terminal hole (21) is provided on the positive busbar (2) at the position corresponding to the positive terminal (4), and a negative terminal hole (31) is provided on the negative busbar (3) at the position corresponding to the negative terminal (5). The lower end of the positive terminal (4) is fitted with the positive terminal hole (21) and extends to the bottom of the positive busbar (2) and is wrapped by the potting layer (111). The lower end of the negative terminal (5) is fitted with the negative terminal hole (31) and extends to the bottom of the negative busbar (3) and is wrapped by the potting layer (111).

4. The terminal structure of the thin-film capacitor according to claim 3, characterized in that: A positive terminal extension flange (42) that fits into the positive terminal hole (21) is formed at the center of the lower end of the positive terminal (4), and a negative terminal extension flange (52) that fits into the negative terminal hole (31) is formed at the center of the lower end of the negative terminal (5).

5. The terminal structure of the thin-film capacitor according to claim 1, 2, or 3, characterized in that: The potting layer (111) is an epoxy resin layer.

6. The terminal structure of the thin-film capacitor according to claim 1, 2, or 3, characterized in that: The positive busbar (2) and the negative busbar (3) are E-shaped with their positions staggered and face to face.

7. The terminal structure of the thin-film capacitor according to claim 6, characterized in that: The positive busbar (2) and negative busbar (3) are made of copper.

8. The terminal structure of the thin-film capacitor according to any one of claims 1 to 4, characterized in that: A positive terminal electrical connection hole is formed at the upper center of the positive terminal (4), and a negative terminal electrical connection hole (53) is formed at the upper center of the negative terminal (5).

9. The terminal structure of the thin-film capacitor according to claim 8, characterized in that: The positive terminal (4) and negative terminal (5) are made of metal materials with high conductivity and high mechanical strength.

10. The terminal structure of the thin-film capacitor according to claim 9, characterized in that: The high conductivity and high mechanical strength metallic material is copper or a copper alloy, and the copper alloy is chromium-zirconium copper.

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